Blackout 2004? If you were spared last summer's massive power failure, you may not be so lucky next time.

Rachel Ridge, her mom, and sister were getting haircuts at a shopping center near Cleveland, Ohio, when the power blanked out on August 14. "Everyone had different opinions," says the 11-year-old. "At first we thought it might be terrorism." Despite the scare, the three moved onto a patio with their hairdresser to finish the cuts and even do Rachel's highlights.

Not everyone had it so easy. If you were one of 50 million people left in the dark by "Blackout 2003"--which paralyzed much of the Northeastern U.S. and Canada--you may have been stuck on a pitch-black subway or elevator, or scraped through the next 24 hours (or days) at home without electricity, gas, phone, or running water.

As SW goes to press, utility experts and government officials are debating exactly what went wrong and why. But there's one thing on which most of them agree: "We will always have blackouts," says Hoff Stauffer, of Cambridge Energy Research Associates. That may be due to the fact that the U.S. burns more electricity than any other nation in the world--one quarter of all electric power produced on Earth.

So just what did happen on August 14? What are experts doing to prevent Blackout 2004? And what can you do to help? Turn the page to learn all in our special Q&A.

WHAT WENT WRONG IN THE BLACKOUT OF 2003?

Around 2:00 p.m. EST  last August 14, a high-voltage power line in Ohio overheated and sagged into a tree, shorting out the line. This isolated incident, experts think, caused electricity to flow into other nearby lines--and one of them also over loaded and failed. Result: a chain reaction that shut down power plants in the U.S. and Canada. The shutdown actually helped the plants avoid damage from power surges racing through the wires. But it caused the lights to go out throughout the Northeastern U.S. and Canada at 4:11 p.m. EST.

How could such a blackout occur in the first place? "It was a combination of random events happening at the same time, and with a few human errors," says Stauffer. "It's hard to know where to start." The one place almost everyone looks for answers, however, is in America's soaring demand for electricity serviced by an outdated electrical power grid (network that connects power stations to homes and businesses).

The good news: The grid's safety systems worked as planned, shutting down those parts that might be damaged. Had the systems not worked, "instead of a blackout for a couple of days, we would have had one for several months," says Jack Hawks, a vice president at the Electric Power Supply Association. And unless the U.S. can curb its craving for electricity, Hawks's scenario might become grim reality.

SO WHAT IS ELECTRICITY ANYWAY?

Electricity is a form of energy created by the movement of electrons (negatively charged particles that orbit the nucleus, or center of an atom). It's used to power everything from light bulbs to sewage systems. We measure electricity in several ways:

* AMPERES (amps) measure the number of electrons, or the current, flowing through a wire. One amp is equal to 6.25 x [10.sup.28] electrons flowing per second.

* VOLTS measure the amount of force an electric current carries through a wire. Example: A 9V battery has 6 times more force than a 1.5V battery.

* WATTS measure the ability of electricity to do its work--power a fridge or run your computer. If you lift an 8-ounce glass of water in one second, you're working at the rate of about 1 watt. Because 1 watt is such a tiny amount of power, electricity is measured in kilowatts.

HOW IS ELECTRICITY MADE?

Most power plants crank out electricity by first creating super-hot steam at more than 315[degrees]C (600[degrees]F). The steam blows against the blades of a large fan, called a turbine, which turns a generator (a machine that produces electricity). But there are other ways to turn a generator, from flowing water to wind (think wind farms, and see SW 4/18/03). You could even pedal a stationary bike attached to a generator and create electricity, but you'd only make enough power to burn a couple of light bulbs--and only until you got tired.

More than two thirds of electricity in the U.S. comes from burning fossil fuels (fuels made of decayed plants and animals) such as coal, oil and natural gas. Coal alone produces the steam for half of our electricity.

CAN WE EXPECT ANOTHER BIG BLACKOUT?

Several majjor blackouts have occurred over the past 20 years, as well as many smaller power failures--and most experts expect more of both in the future. Some blackouts are accidentally triggered by bad weather (mostly ice storms and lightning), others by equipment failure or human error. But the power industry is currently working on ways to help reduce the likelihood that small events, like a tree being in the wrong place at the wrong time, grow into massive blackouts.

Because many parts of the electrical grid are decades old, they can't meet the country's huge and growing appetite for electricity. "We can't tolerate a system that's this brittle," former U.S. Energy Secretary Charles Curtis told Time magazine. Building more power stations and transmission lines is one way to reduce the load on the system.

Another option: Better control the system we already have. The California-based Electric Power Research Institute has proposed a new technology that uses sensors to monitor the temperature at points along the transmission line--allowing central computers to divert, the most energy possible through wires without causing a meltdown or sagging. Although conservation probably wouldn't have prevented the complicated events leading to the blackout of 2003, "if we demand less electricity, there will be less of a strain on the grid," says Debbie Boger of the Sierra Club. And that could reduce future power failures.

WEB SEARCH: You don't have to be in the dark about electricity. Use the Internet to find five ways you can help conserve.

HOW DO I GET ELECTRICITY?

Everything from the generator at the power plant to your TV is part of a grid that shuttles electricity across the nation. The grid allows different places to share power whenever needed. Usually, if a power plant or high-voltage line has to be shut down for repairs, other parts of the grid can make up for the loss.

1 POWER PLANT

A plant converts heat into electricity. Most power plants burn fossil fuels like coal, oil, or gas for heat.

2 STEP-UP TRANSFORMER 

A step-up transformer cranks up the voltage, or the force of electrical current. This jolt sends the current over long distances, but it also generates massive heat in the wires.

3 TRANSMISSION LINES

More than 960,000 km (600,000 mi) of power lines crisscross the U.S.--enough wire to circle the Earth 26 times. The lines can carry up to 300,000 volts of electricity, making them extremely dangerous.

4 STEP-DOWN TRANSFORMER 

Because electrical appliances can't handle so much power, the voltage is reduced to a few thousand volts at a step-down transformer before it's delivered to homes and businesses.

5 CUSTOMERS

When electricity is finally delivered to neighborhoods, it's a safe 240 or 120V--the right level to power factories, offices, homes, and mass transit.

Did You Know?

* About 25 percent of all electricity consumed in the U.S. is used to generate light. And only 10 percent of the energy that goes into a light bulb provides illumination. The rest turns into wasted heat.

* New York City officials 'logged 800 elevator rescues, 80,000 emergency calls, and made 305 arrests during the blackout of 2003.

* Turning the thermostat up just one degree in the summer and down in the winter can reduce your family's energy consumption by as much as 5 percent.

* The last major blackout happened in August of 1996, when a region stretching south from Oregon to California and east to Texas lost power. Soaring summer temperatures led customers to crank up their air conditioning, which then caused power lines to overload and sag into trees.

Cross-Curricular Connection:

History/Language Arts: Benjamin Franklin was credited with discovering that lightning is electricity, while Thomas Edison invented the light bulb. Research their lives and write a fictional conversation between these two great inventors in which they discuss how their ideas are used today.

Critical Thinking:

Look at the bar graph on p 6. What factors might account for energy consumption in the top 5 countries? As a class, form five groups--one to research each country. In groups, prepare a poster that helps explain your assigned country's energy use. Discuss the differences as a class.

For full details, including diagrams; of the blackout of 2003 read these two articles:

"Fade to Black," Newsweek, Aug. 25, 2003.

"Lights Out," Time, Aug. 25, 2003.

Find energy games, puzzles, fact sheets, lesson plans and more at the U.S. Department Of Energy's kid site: www.energy.gov/engine/content.do?BT_CODE=KIDS

Learn about the nation,s electric grid and how blackouts happen at: people.howstuffworks.com/blackout.htm